Technical Field
The present disclosure relates to an apparatus for prestressing a concrete floor of an inclined shaft wall, which is applicable to supporting and protecting engineering for inclined shafts, tunnels, roadways, chambers and the like in high-water-pressure and high-expansion stratums in the fields of mine construction, water conservancy, traffic, municipal administration and the like.
Description of the Related Art
In stratums with large burial depths and high water pressures, there are such waterproof requirements for design and construction of inclined shaft walls that floors of the shaft walls must make sure that no tension failures occur on upper surfaces under the high water pressures. However, due to the characteristics that concrete is pressure-proof but lack of tensile strength, the floor of the inclined shaft wall often has an extremely large design thickness and extremely high steel content, or even the floor must be designed as an inverted arch with a small curvature radius, which greatly increases the construction difficulty. Even so, floor concrete of the shaft wall still often causes a sudden water burst and even a mine flooding accident because of top surface cracking.
At present, most of inclined shaft walls in water-bearing stratums are designed as flat and straight floor structures or “flat-top and curved-bottom” concrete slab structures with bottom surfaces having certain radians. Due to the limitation of a construction process, it is very difficult to design the floor as an inverted arch structure with an extremely small curvature radius, resulting in that the floor structure of the shaft wall often hardly meets a requirement for resisting a high water pressure at the lower part, thereby remaining a risk of bending and tension failures caused by a bulged middle part of the floor. Therefore, for the inclined shaft walls with non-circular interfaces in the water-bearing stratums, it is in urgent need of taking measures to prevent the bending and tension failures of the floors.